Airplane propeller and means for adjusting same



Dec. Z8, 1948. J. G. LITTRELL. 2,457,576

AIRPLANE PROPELLER -AND MEANS FOR `ADJUSTING SAME4 1 2 'Sheets-Sheet 1 Filed July 20, 1944 N E l Y 9 v Cttorneg Dec. 28, 1948, J. G. LITTRELL 2,457,576

AIRPLANE PROPELLER AND MEANS FOR ADJUSTING SAME Filed July 2o, 1944 2 sheets-sheet 2 e?. vvvv or Patented Dec. 28, 1948 UNITEDsTATE-s PATENT oFFlcE AIRPLANEPRQPELLERANDMEANS Fon ADJUSTING Y John G. Littrell, San. Antonio, Tex.

' Applicatiqiiuuly 2o, 1944, No. 545,767

As. claims. (cl. 170g-renin) The present invention relates to improvements airplane propellers and means for adjusting same and more particularly relates to a mechanism incorporated in the propeller structure and rotating therewith, whereby the blades may be both angularly adjusted as to pitchl and also moved in fand out radially, to change the elongation of the blade fromthe propeller center of rotation.

An object of the invention is to accomplish the two purposes of pitch changing and radial elongation by the simply constructed, compact and efliacierrtlyv operating mechanism that. lends itself to inclusion within small compassin -the `hollovi7 shaft of the propellers.

Another object of the invention is to provide a device'fcr the above purposes which will be faith tal' in performance and so constructed andarranged'as to avoid the lpossibility of binding. or

'freezing of the parts.

vWiththe foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

` In the drawings, in which the samef reference characters indicate the same parts throughout the several views,

Figure 1 is a fragmentary longitudinal section taken through an improved propeller constructed i-naccordance with the presen-t invention ;7

Figure 2 is a transverse section taken on the line 2-2 of Figure 1;

Figure 3 is a similar section taken on the line 3 3 in Figure 1, on an enlarged scale;

Figure 4 is a fragmentary longitudinal cross section of the propeller socket showing the inclined or spiral grooves;

lFigure 5 is a cross section taken on an enlarged scale on the line 5 5 of Figure l;

Figure 6 is a similar view taken on line 5--6 also in Figure 1; and

Figure '1 is a front elevation, taken on a small scale of a two-blade propeller with the outer position of the blades indicated in dotted lines.

Referring more particularly to the drawings, I0 designates a control shaft, concentric with and mounted within the tubular driving shaft 55 and having a ring gear I4 mounted Within hub housing II, of a conventional airplane propeller construction having tubular propeller receiving sockets I2 radiating therefrom. For purposes of illustration only, one such propeller receiving socket has been shown in the accompanying drawings, best seen in Figure l; however it is understood that any desired number of such l 2` sockets may be4 radially mounted about the hub housing, A propeller blade I3 is slidably and rotatably received over the receiving socket lf2.

The shaft t0 dri-ves a ring gear i4 with which rnesll-one.l or more `pinions I5, one for each propeller blade. The pinion I5 is fastened on a screw shaft L6 Amounted to rotate, but against end'wise or axial movement, :in a bearing I1.. The thread of the shaft is indicated at I8, the same engaging with complemental threads upon a traveling nut IES. lMade fast to the nut is a sleeve 20 having two or more radial keys 2I projecting outwardly and sliding in .slotted'guides22 fixed by .fastenings 23 tothe inside wall of the tubular propeller socket 132.

The outer end of the sleeve 20; slipped over a reduced neck 24 of a .slidable cross head 25 and `ment at both; cross heads 25 and 211.

Spiral grooves 36 in, the internalv walls of the tubular propeller socket I`2 receive keys 3'1 provjecting from the outer cross head 2.1 to cause rotation of this outer cross head on the axial sliding of such cross head. A spindle 38 is received at its inner end into a socket 39 of the outer cross head 21 and a pin 40 secures the spindle to the cross head. A coil spring 4I is Wound in a suitable number of convolutions around the spindle 38 having one end abutting against the outer cross head 21 and its outer end engaging against a web 42 projecting inwardly from a connecting ring 43. Such ring is threaded, as indicated at 44, to mate with threads upon the reduced outer end of the tubular propeller socket I2. The web 42 is apertured at 45 to slidingly receive the spindle 38 therethrough. The ring 43 carries an extension ring 46 outwardly of web 42 to envelope the reduced or stepped-down end 41 of the propeller blade I3. A bearing portion 48 of the blade outwardly of the reduced part 41 lies between this reduced end 41 and a groove 49 of the blade root. The groove 49 receives an inturned flange 50 of a tapered sleeve 5I movable with the blade I3 and enveloping and operable upon the outer portion of the tubular propeller socket I2 to conceal, and exclude foreign matter Referring more particularly to Figure 2, one

form of drive for the ring gear I4 is shown in which the shaft IB enters through `anl outer'k This outer shaft55`may be y tubular shaft 55. connected to the airplane engine for rotating the propeller as a whole. The inner shaft l'may be connected to any adjusting mechanism, for in-i stance to an electric motor and its reduction gear) ln operation, as indicated in Figure 7, the pro-j peller blades I3 may be adjusted outwardly within the range of thedotted lines. Simultaneously with this adjustment, the bladesk II are also rotated angularly about their longitudinal axes to eifect pitch changes. In order to accomplish this result, the control shaft IU is turned the desired number of 'revolutions in a like `manner. rotating the ring gear I4 and-the enmeshed pin-; On i5.

direction of rotation.

cross heads 25 and 2l. The outer cross head, by

virtue of the groove 36 and key 3l construction,y f' will be vrotated as it moves outwardly to secure The rotary motion of the outer pitch change. cross head 2'I is communicated through the spin dle 38 'and to the blade I3.

The coil spring 4I will be compressed incident to the outer movement of the cross heads and will act to expand inwardly and drive the cross heads inwardly when the power is removed from the shaft IB. Thus the parts are biased to an inner position.

The consequent rotation of thescrew shaft I6 will cause the nut I9 to travel in or out on such screw shaft I6 in accordance with its In moving out, the nut` i9 will carry with it the sleeve 2li and the two The drawings show only one embodiment oi" the invention, which isbest known to me at this time, but it will be understood that these drawings are only illustrative of a construction and one embodiment of the invention.

It will be 2' understood that the invention is susceptible of embodiment in various other forms, al1 within the scope of the following claims.

What is claimed is:

1. In an airplane propeller, a hub, tubular propeller sockets radiating from said hub, a blade movable inwardly and outwardly of said hub with respect to said tubular propeller sockets and also adjustable angularly, substantially about the axis of the socket', a spindle, one end of which is axed to said blade and located concentricaliy within said socket and the i other end of which is aixed to a first cross head,

-a second cross head movable radially in saidl socket and fixedly coupled to said blade means to move said first cross head radially in said socket, and means between said cross heads and sockets for requiring said second cross head to rotate incident to its radial traverse.

2. An'airplane propeller as claimed in claim 1 wherein -a spring helix envelops the spindle which links the propeller-bladev with the ycross head and biases same to inner-positionoandis compressed by the outward movement of lsaid cross head. Y m1',

3. An airplane propeller as claimed in claim'l wherein the means for rotating said second cross head comprises spiral grooves in said tubular pro;- peller sockets for receiving and guiding keys carried by said second cross head. y

l JOHN G,

REFERENCES CITED The following references arey of recordgthe leof this patent: l z'.

y UNITED STATES PATENTS Number ,Name y f Date 1,365,132 VeSSey 113411.11, 1,921

1,754,192 ValiVlel Apr.'8,` 1r930 2,145,413 Beleld Jan."31,19 3 9 2,146,481 Manning l; Feb.@7,w1939 2,163,482r Cameron June 20, 1939 2,282,077 vMeer@ May 5,1942 2,403,946 NayeS July 16,A 1946 2,415,421 y FilippS Feb. .11, 1947 FOREIGN PATENTS Y v Number Country l Date i 506,246 Great Britain -..n May 24, 1939 859,700 France Dec. 24, 1940 

